AMD Ryzen 5 PRO 7645 vs Intel Core i9-11900 Comparison

The AMD Ryzen 5 PRO 7645 is the decisive winner in this matchup, taking 15 of 17 head-to-head benchmark comparisons against the Intel Core i9-11900. While the Intel chip retains two specific math-heavy wins, the AMD processor’s lead in rendering, encryption, and single-thread performance is both consistent and substantial, making it the superior choice for most workloads.

Head-to-Head Benchmarks

The most striking result is in the Cinebench suite, where the AMD Ryzen 5 PRO 7645 posts a uniform 14.4% advantage across every test. In Cinebench R23 multi-core, the AMD scores 21,710 against Intel’s 18,985, while in single-core it reaches 3,065 versus 2,680. The same 14.4% delta appears in R20 (9,118 vs. 7,973 multi-core; 1,287 vs. 1,125 single-core) and R15 (2,188 vs. 1,913 multi-core; 308 vs. 270 single-core). This consistency indicates the AMD architecture delivers a broad efficiency gain, not a workload-specific edge.

The single largest percentage victory belongs to the AMD in the PassMark find prime numbers test, where it scores 198 against Intel’s 63—a 214.3% difference. This result highlights a massive advantage in integer-heavy algorithmic work that relies on per-core throughput. The AMD also dominates PassMark physics with a 63.6% lead (1,598 vs. 977), suggesting superior handling of real-time simulation calculations.

Data encryption shows a 19.5% win for AMD (16,657 vs. 13,942), and extended instructions testing gives AMD an 11% edge (21,813 vs. 19,654). In PassMark multi-thread, AMD leads by 13.5% (25,489 vs. 22,456), and single-thread performance is 8.3% higher (3,652 vs. 3,373). Random string sorting favors AMD by 4.5% (34,557 vs. 33,054), while data compression is nearly tied with AMD ahead by just 0.4% (286,298 vs. 285,159).

Intel’s two wins come in floating-point math and integer math. In floating-point, Intel scores 48,948 against AMD’s 45,202, a 7.7% advantage. The integer math result is more pronounced: Intel reaches 83,893 versus AMD’s 74,782, representing a 10.9% lead. These are the only areas where the older Intel design outperforms, and they are specific to raw arithmetic throughput rather than broader application performance.

Where Each One Wins

The AMD Ryzen 5 PRO 7645 wins in every category requiring sustained multi-core execution, including all Cinebench rendering workloads, PassMark multi-thread, physics, and encryption. Its 14.4% lead across the entire Cinebench series indicates that content creation, 3D rendering, and video encoding tasks will see consistent improvements. The 214.3% margin in prime number finding makes it the clear pick for cryptography, scientific computing, and any workload dependent on modular arithmetic.

The AMD also excels in single-threaded performance, with an 8.3% lead in PassMark single-thread and 14.4% in Cinebench R23 single-core. This translates to faster response times in everyday applications, older software, and lightly-threaded games. The 11% edge in extended instructions suggests better support for SIMD and specialized instruction sets, which benefits codecs and data processing libraries.

The Intel Core i9-11900 wins in floating-point math and integer math by 7.7% and 10.9%, respectively. These workloads are relevant to financial modeling, scientific simulations, and certain engineering applications that rely heavily on arithmetic throughput. However, the practical impact is limited because the Intel CPU’s overall multi-thread deficit of 13.5% means that even these wins are unlikely to overcome its broader performance disadvantage in mixed workloads.

FAQ

Q: Which CPU is faster in Cinebench R23 multi-core?

A: The AMD Ryzen 5 PRO 7645 scores 21,710, which is 14.4% higher than the Intel Core i9-11900’s 18,985.

Q: Does the Intel Core i9-11900 win any benchmarks?

A: Yes, it wins PassMark floating-point math (48,948 vs. 45,202, a 7.7% lead) and PassMark integer math (83,893 vs. 74,782, a 10.9% lead).

Q: How large is the AMD’s advantage in single-threaded performance?

A: The AMD leads by 8.3% in PassMark single-thread (3,652 vs. 3,373) and by 14.4% in Cinebench R23 single-core (3,065 vs. 2,680).

Q: What is the biggest benchmark gap between these two CPUs?

A: The largest gap is in PassMark find prime numbers, where the AMD scores 198 versus Intel’s 63, a 214.3% difference.

Q: Are the two CPUs close in overall average benchmark score?

A: The AMD has an average benchmark score of 32,446, while the Intel scores 32,226. The AMD also ranks at the 83rd percentile versus the Intel’s 82nd percentile.

Q: Which CPU is better for data compression tasks?

A: The AMD is marginally ahead with a score of 286,298 versus Intel’s 285,159, a difference of just 0.4%.

Specification Differences

The core configurations differ significantly. The AMD Ryzen 5 PRO 7645 has 6 cores and 12 threads, while the Intel Core i9-11900 has 8 cores and 16 threads. Despite the Intel having two more cores, the AMD still wins most multi-threaded tests. Clock speeds also differ: the AMD has a base clock of 3.80 GHz and a boost clock of 5.10 GHz, while the Intel has a base of 2.50 GHz and a boost of 5.20 GHz.

The memory subsystems are different generations. The AMD supports DDR5 with a dual-channel bus and a bandwidth of 83.2 GB/s, whereas the Intel supports DDR4 with a dual-channel bus and 51.2 GB/s bandwidth. The AMD also supports ECC memory, which the Intel does not. PCIe connectivity differs as well: the AMD offers Gen 5 with 24 lanes, while the Intel provides Gen 4 with 20 lanes.

Cache allocations are distinct. The AMD has 1 MB of L2 cache per core and 32 MB of shared L3 cache, while the Intel has 512 KB of L2 per core and 16 MB of shared L3. Both have 64 KB of L1 cache per core. Integrated graphics are present on both: the AMD features Radeon Graphics, and the Intel includes UHD Graphics 750.

The market positioning differs. The AMD is classified for the server/workstation segment and remains in active production, while the Intel is a desktop part that is end-of-life. The AMD uses Socket AM5, and the Intel uses Socket 1200. The Intel has a launch MSRP of $439; the AMD has no listed launch MSRP.

Architecture Differences

The fundamental architecture gap is generational. The AMD Ryzen 5 PRO 7645 uses the Zen 4 architecture on a 5 nm process node from TSMC, while the Intel Core i9-11900 uses the Rocket Lake architecture on Intel’s 14 nm process. The AMD’s transistor count is 6,570 million on a 71 mm² die, whereas the Intel’s die is 276 mm² with no transistor count listed.

The AMD’s codename is Raphael, part of the 7000 series, and it uses the Ryzen 5 generation naming. The Intel’s codename is also Rocket Lake, part of the Core 11th Gen, and uses the Core i9 generation naming. The production status diverges sharply: the AMD is active, while the Intel is end-of-life.

Cache architecture shows the AMD’s advantage in shared L3 capacity (32 MB vs. 16 MB) and per-core L2 (1 MB vs. 512 KB). The AMD’s memory bandwidth of 83.2 GB/s is 62.5% higher than the Intel’s 51.2 GB/s, which aligns with the DDR5 versus DDR4 split. The AMD also has PCIe Gen 5 support versus the Intel’s Gen 4, and more lanes (24 vs. 20).

The Intel has a higher boost clock by 0.10 GHz (5.20 vs. 5.10), but this does not translate into single-thread wins. The AMD’s newer process node and architecture compensate for its lower core count, delivering better performance per clock and per watt in most tests.

The Verdict

The data points to the AMD Ryzen 5 PRO 7645 as the stronger processor for the vast majority of users. Its 14.4% lead across all Cinebench tests makes it the better choice for rendering, video editing, and any multi-threaded productivity application. The 8.3% single-thread advantage ensures snappier general responsiveness, and the 19.5% encryption lead improves security-related tasks. The 214.3% margin in prime number finding is decisive for scientific computing and cryptography.

The Intel Core i9-11900 should only be considered by users whose workloads are dominated by raw floating-point or integer math, where it holds advantages of 7.7% and 10.9%, respectively. However, these wins are narrow compared to the AMD’s sweeping multi-core dominance. The Intel’s higher core count (8 vs. 6) does not overcome the AMD’s architectural efficiency, as evidenced by the 13.5% multi-thread deficit.

Given that the AMD is in active production and the Intel is end-of-life, the AMD also offers a forward-looking platform with DDR5 and PCIe Gen 5 support. The Intel’s launch MSRP of $439 provides context, but its performance profile does not justify selecting it over the AMD for general-purpose computing. The verdict is clear: choose the AMD Ryzen 5 PRO 7645 for essentially all workloads except those specifically requiring maximum integer or floating-point arithmetic, where the Intel Core i9-11900 retains a niche edge.